Overview

Evaluate the given expression when the user changes the input. The expression is evaluated immediately, unlike the JavaScript onchange event which only triggers at the end of a change (usually, when the user leaves the form element or presses the return key).

The ngChange expression is only evaluated when a change in the input value causes a new value to be committed to the model.

It will not be evaluated:

• if the value returned from the $parsers transformation pipeline has not changed
• if the input has continued to be invalid since the model will stay null
• if the model is changed programmatically and not by a change to the input value

Note, this directive requires ngModel to be present.